Arrangement for removing condensed moisture from a display area of ​​a windshield

Abstract

Arrangement for removing condensed moisture from a display area of ​​a windshield, comprising: - a windscreen (10) comprising an outer pane (1) with an outer surface (I) and an inner surface (II) and an inner pane (2) with an outer surface (III) and an inner surface (IV), wherein the inner surface (II) of the outer pane (1) and the outer surface (III) of the inner pane (2) are connected to each other via a thermoplastic intermediate layer (3), which has a transparent see-through area (D) and an opaque masking area (M) and which has a display area (A) that is located in the masking area (M), and which is provided at least in the display area (A) with a reflective layer (7) suitable for reflecting radiation in the visible spectral range, wherein at least in part of the display area (A) on the interior surface (IV) of the inner disc (2), a hydrophobic coating (8) is arranged as the uppermost exposed layer, - an ultrasonic transmitter (20) which is assigned to the windshield (10) in such a way that it is suitable to set at least the said part of the display area (A) into vibration.

Description

[0001] The invention relates to an arrangement for removing condensed moisture from a display area of ​​a windshield, a display system for a vehicle containing said arrangement, and a vehicle equipped with said arrangement or said display system.

[0002] Windshields for vehicles, particularly motor vehicles such as passenger cars, are designed as laminated glass (laminated safety glass), consisting of an outer pane and an inner pane laminated together via a thermoplastic intermediate layer. They typically have an opaque masking area, which is designed as a peripheral edge region and surrounds a central see-through area. The opaque masking area primarily serves to protect the adhesive used to bond the windshield to the vehicle body from UV radiation. The masking area is typically formed by a black masking print on the surface of the outer pane facing the intermediate layer.

[0003] Modern vehicles are increasingly being equipped with display systems that project graphic images directly onto the windshield. A well-known example of this is head-up display (HUD). An imaging unit (specifically a projector) located near the dashboard projects images onto the view-through area of ​​the windshield, reflects them, and is perceived by the driver as a virtual image (as seen from the driver's perspective) behind the windshield.

[0004] Such a HUD can be operated with s-polarized radiation, which is reflected by the interior surface of the outer pane and by the exterior surface of the inner pane. To avoid ghosting, the two reflections are typically superimposed using a wedge-shaped intermediate layer. Such HUDs are known, for example, from WO2009071135A1, EP1800855B1, or EP1880243A2. However, it has proven advantageous for such display systems to be operated with p-polarized radiation. Firstly, the display images can then be easily perceived even by people wearing polarization-selective sunglasses. Secondly, disturbing ghosting can be avoided because the angle of incidence of the radiation from the imaging unit is typically close to the Brewster angle, so that the radiation is hardly reflected by the glass surfaces.Instead, the windshield is equipped with a reflective layer suitable for reflecting the p-polarized radiation to generate the display image. Examples include DE102014220189A1, EP3187917B1, and WO2021104800A1.

[0005] It has also been proposed to use the opaque masking area as a display surface for such a display system. For this purpose, a display area in the masking area is illuminated by an imaging unit (in particular a screen). Examples include DE102009020824A1, WO2022073894A1, and WO2022073860A1. In this way, displays for the driver that were previously located in the dashboard area can be presented on the windshield itself. Examples of such displays include the driving speed, the time, the engine speed, the navigation system display, information on speed limits (traffic sign recognition), the image from a rear-facing camera, and various status displays regarding the vehicle's condition.

[0006] At low outside temperatures, it is common for the interior surface of the windshield to become covered with condensed moisture when the vehicle is stationary (fogging). This makes the display unreadable. The display area is typically located in the section of the masking area adjacent to the lower edge of the windshield, i.e., below the view-through area. Since this lower edge is relatively far away from the driver due to the steeply inclined installation position of the windshield, particularly in passenger cars, the display area is difficult for the driver to reach, making it difficult to remove the condensed moisture manually.To make matters worse, the windshield heating devices, especially the outlet nozzles of the vehicle's ventilation system, are typically directed primarily at the view-through area of ​​the windshield to ensure visibility through the windshield as quickly as possible. It therefore takes a comparatively long time for the masking area at the lower edge to be heated, which leads to the removal of condensed moisture.

[0007] There is therefore a need for windshield assemblies capable of quickly and easily removing condensed moisture from a display area in the masking area.

[0008] WO2022238101A1 discloses a windshield with a display area that can be actively heated by an integrated heating element, in particular heating wires. However, the removal of condensed moisture by active heating is characterized by high energy consumption.

[0009] CN206704151U proposes attaching an ultrasonic transmitter to the windshield, which is capable of causing the windshield to vibrate, causing water droplets (condensed moisture or melted ice) to roll off the windshield. CN117896597A proposes using ultrasound to remove moisture from the lens of a camera installed in the vehicle.

[0010] The present invention is based on the object of providing an improved arrangement for removing condensed moisture from a display area of ​​a windshield, which ensures a quick and technically simple removal of the moisture mist.

[0011] The object of the present invention is achieved by an arrangement according to claim 1. Preferred embodiments emerge from the subclaims.

[0012] The arrangement according to the invention for removing condensed moisture from a display area of ​​a windshield comprises a windshield and at least one ultrasonic transmitter associated with the windshield.

[0013] The windshield is designed as a composite pane and comprises an outer pane and an inner pane, which are bonded together by a thermoplastic intermediate layer. The windshield is intended to separate the interior (vehicle interior) from the exterior environment in the window opening of a vehicle facing forward in the direction of travel. For the purposes of the invention, the "inner pane" refers to the pane of the windshield facing the interior. The "outer pane" refers to the pane facing the exterior environment.

[0014] The outer pane and the inner pane each have an outer surface and an inner surface, and a circumferential side edge surface extending therebetween. For the purposes of the invention, the "outer surface" refers to the main surface intended to face the outside environment in the installed position. For the purposes of the invention, the "inner surface" refers to the main surface intended to face the interior in the installed position. The interior surface of the outer pane and the outer surface of the inner pane face each other and are connected to one another via the thermoplastic intermediate layer.

[0015] The windshield has a transparent see-through area and an opaque masking area. The see-through area is intended for viewing. The see-through area preferably has a light transmittance of at least 70%. Light transmittance here refers to the total transmittance, determined by the method specified in ECE-R 43, Annex 3, Section 9.1 for testing the light transmittance of motor vehicle windows. For the purposes of the invention, a masking area refers to an area of ​​the windshield through which viewing is not possible. The light transmittance of the masking area is less than 5%, preferably less than 2%, more preferably less than 0.5%, and most preferably less than 0.1% (in particular essentially 0%). The masking area is formed by an opaque element, for example an opaque print or an opaque film.

[0016] The windshield has a display area located in the masking area. The display area is designed to be illuminated by an imaging unit to generate a display image perceivable by the vehicle occupants, in particular the driver (interior display image). During operation, the imaging unit illuminates the display area of ​​the windshield, where the radiation is reflected toward the viewer (driver), creating a virtual image.

[0017] The windshield is provided with a reflective layer, at least in the display area. The reflective layer is suitable and intended to reflect radiation in the visible spectral range, in particular the radiation from the imaging unit, to generate the display image. The opaque element, which forms the masking area, is arranged behind the reflective layer in the line of sight from the vehicle interior to the external environment, so that the latter can be illuminated by an imaging unit in the vehicle interior. Thus, in the installed position, the reflective layer is at a shorter distance from the vehicle interior (and any imaging unit) than the opaque element and at a greater distance from the external environment.

[0018] According to the invention, a hydrophobic coating is arranged on the interior-facing surface of the inner pane in at least part of the display area. The hydrophobic coating is the uppermost layer on the interior-facing surface and is therefore exposed to the vehicle interior.

[0019] The ultrasonic transmitter is assigned to the windshield in such a way that it is capable of causing at least the said portion of the display area in which the hydrophobic coating is present to vibrate. This initially means that the said portion is at least partially caused to vibrate—that is, that at least a portion of the portion of the display area provided with the hydrophobic coating is caused to vibrate. Preferably, the portion of the display area provided with the hydrophobic coating is caused to vibrate completely.

[0020] The hydrophobic coating increases the contact angle for water on the interior surface of the inner pane. This means that condensed moisture does not form a continuous liquid film, but instead beads up and forms separate water droplets. The wettability of the interior surface is reduced. The vibrations caused by the ultrasonic transmitter cause these water droplets to drip, slide, or roll off the surface. This removes the condensed moisture from the display area. Furthermore, it is also possible to use the ultrasonic transmitter not only to remove moisture condensation, but also to clean the display area. The operation of the ultrasonic transmitter requires comparatively little energy, especially compared to heating the display area with an integrated heating element. These are major advantages of the present invention.

[0021] The hydrophobic coating can be applied to only one part of the display area, while another part is not coated. This can be used, for example, to quickly remove moisture from a part of the display area where particularly important information for the driver is displayed. In a preferred embodiment, however, the entire display area is coated with the hydrophobic coating, and the ultrasonic transmitter is designed to vibrate the entire display area. This advantageously removes moisture from the entire display area.

[0022] In an advantageous embodiment, only the display area of ​​the windshield is provided with the hydrophobic coating. However, for manufacturing reasons, it may be desirable for the hydrophobic coating to extend slightly beyond the display area. Preferably, the hydrophobic coating protrudes circumferentially by a maximum of 5 cm beyond the display area, particularly preferably by a maximum of 2 cm.

[0023] According to the invention, the hydrophobic coating is arranged on the interior-side surface of the inner pane and forms the exposed uppermost layer there. The hydrophobic coating can be the only coating on the interior-side surface. It is then arranged directly on the surface of the inner pane and is in direct contact with it. However, it is also possible for a further coating to be arranged between the hydrophobic coating and the interior-side surface of the inner pane. This further coating can be the reflective layer or another functional coating, for example an IR-reflecting, in particular emissivity-reducing, coating or a scratch-resistant coating. The hydrophobic coating is transparent, so that the reflective layer can be irradiated by the imaging unit through the hydrophobic coating.

[0024] The reflective layer can be arranged on the interior surface (beneath the hydrophobic coating). Alternatively, the reflective layer can be arranged on the exterior surface of the inner pane or the interior surface of the outer pane. Alternatively, the reflective layer can be arranged within the intermediate layer, for example, applied to a carrier film or formed as a reflective film between two thermoplastic layers of the intermediate layer. In principle, the reflective layer can also be arranged on the exterior surface of the outer pane (beneath the opaque element), although this is less preferred.

[0025] The opaque element forming the masking region is preferably arranged on the interior-side surface of the outer pane. The opaque element can alternatively be arranged on the exterior surface of the inner pane or on the interior surface of the inner pane (beneath the reflective coating and the hydrophobic coating). In principle, the opaque element can also be arranged on the exterior surface of the outer pane, although this is less preferred. The opaque element can also be arranged within the intermediate layer, for example, as or on a film between two thermoplastic layers of the intermediate layer.

[0026] Relative terms such as "over", "under", "above", "beneath", "top", "bottommost" in relation to layer sequences always refer to the order starting from the substrate surface on which they are deposited. A first layer arranged below or beneath a second layer has a smaller distance to the substrate surface than the second layer. A first layer arranged above, above, or on top of a second layer has a greater distance to the substrate surface than the second layer. The bottom layer has the shortest distance and the top layer the greatest distance of all layers to the substrate surface.

[0027] In particular, the following possibilities for the arrangement of hydrophobic coating, reflective layer and opaque element arise: - Opaque element on the outside surface of the outer pane, reflective layer on the outside surface of the outer pane (below the opaque element), hydrophobic coating on the inside surface of the inner pane; - Opaque element on the outside surface of the outer pane, reflective layer on the inside surface of the outer pane, hydrophobic coating on the inside surface of the inner pane; - Opaque element on the outside surface of the outer pane, reflective layer within the intermediate layer, hydrophobic coating on the inside surface of the inner pane; - Opaque element on the outside surface of the outer pane, reflective layer on the outside surface of the inner pane, hydrophobic coating on the inside surface of the inner pane; - Opaque element on the outside surface of the outer pane, reflective layer on the inside surface of the inner pane, hydrophobic coating on the inside surface of the inner pane (above the reflective layer); - Opaque element on the interior surface of the outer pane, reflective layer on the interior surface of the outer pane (above the opaque element), hydrophobic coating on the interior surface of the inner pane; - Opaque element on the interior surface of the outer pane, reflective layer within the intermediate layer, hydrophobic coating on the interior surface of the inner pane; - Opaque element on the interior surface of the outer pane, reflective layer on the exterior surface of the inner pane, hydrophobic coating on the interior surface of the inner pane; - Opaque element on the interior surface of the outer pane, reflective layer on the interior surface of the inner pane, hydrophobic coating on the interior surface of the inner pane (above the reflective layer); - Opaque element within the intermediate layer, reflective layer within the intermediate layer (between opaque element and inner pane), hydrophobic coating on the interior surface of the inner pane; - Opaque element within the intermediate layer, reflective layer on the outside surface of the inner pane, hydrophobic coating on the inside surface of the inner pane; - Opaque element within the intermediate layer, reflective layer on the interior surface of the inner pane, hydrophobic coating on the interior surface of the inner pane (above the reflective layer); - Opaque element on the outside surface of the inner pane, reflective layer on the outside surface of the inner pane (below the opaque element), hydrophobic coating on the inside surface of the inner pane; - Opaque element on the outside surface of the inner pane, reflective layer on the inside surface of the inner pane, hydrophobic coating on the inside surface of the inner pane (above the reflective layer); - Opaque element on the interior surface of the inner pane, reflective layer on the interior surface of the outer pane (above the opaque element), hydrophobic coating on the interior surface of the inner pane (above the reflective layer).

[0028] Preferred embodiments are those in which the opaque element is arranged on the interior-side surface of the outer pane. Also preferred are those embodiments in which the reflective layer is arranged on the interior-side surface of the inner pane. This is advantageous with regard to intensive reflection of the radiation from the imaging unit and the absence of ghost images, regardless of the polarization state of the radiation. Particularly preferred are those embodiments in which the opaque element is arranged on the interior-side surface of the outer pane and the reflective layer is arranged on the interior-side surface of the inner pane.

[0029] The hydrophobic coating results in an increased contact angle between the water and the pane surface compared to the contact angle on the uncoated pane surface. This results in the water wetting the surface less intensively and, in particular, in the formation of separate water droplets rather than a continuous water film. The contact angle corresponds to the angle between the interior-facing surface of the inner pane (or the hydrophobic coating arranged thereon) and the tangent to the surface of a water droplet in the immediate vicinity of said interior-facing surface. The contact angle of water to the interior-facing surface with the hydrophobic coating is preferably more than 80°, more preferably more than 90°, and most preferably more than 100°. This can be achieved by selecting a suitable hydrophobic coating.

[0030] To measure the contact angle, a drop shape analysis must be used. This involves placing a small water droplet with a volume of 0.1 µL to 5 µL, for example 1 µL, onto the surface of the disc coated with the hydrophobic coating. A contact angle measuring device, such as a contact angle goniometer, takes an image of the droplet and analyzes the shape and contact angle between the droplet base and the surface. The measurement is preferably carried out at a room humidity of 30% to 50%, for example 40%, and a room temperature of 20 °C to 25 °C, for example 22 °C. The contact angle is the angle formed by the tangent to the surface of the droplet in the immediate vicinity of the disc surface with the disc surface. The larger the contact angle, the more hydrophobic the surface.A contact angle of over 90° indicates that the surface is highly water-repellent and the droplet assumes a nearly spherical shape. Measurement methods for determining the contact angle of water droplets are generally known to those skilled in the art. Contact angle measuring devices are commercially available, for example, from Krüss or Lonroy.

[0031] The hydrophobic coating can be a ceramic coating based on rare earth oxides (REO). Preferably, the hydrophobic coating is based on or consists of hafnium oxide, zirconium oxide, and / or cerium oxide.

[0032] If a layer of a coating is based on a material, the layer consists predominantly of this material (at least 50 wt%), in particular essentially of this material alongside any impurities or dopants. The proportion of the material is preferably at least 80 wt%, in particular at least 90 wt%.

[0033] The hydrophobic coating can alternatively be based on one or more polymers. Particularly preferably, silicon oxide particles, in particular silicon oxide nanoparticles, are incorporated into the polymer coating. Such polymer coatings can be produced, for example, using hexamethyldisiloxane. For example, the hydrophobic coating consists of at least one polymethylsiloxane and silicon oxide particles, in particular silicon oxide nanoparticles, incorporated therein. Polymethylsiloxanes exhibit water-repellent properties and are therefore particularly suitable for use in the hydrophobic coating.For the purposes of the invention, “polymethylsiloxane” means in particular one or more of the following compounds: polymethylhydrogensiloxane (PMHS), polydimethylsiloxane (PDMS), methylphenylpolysiloxane, trimethylsiloxy-end-crosslinked polydimethylsiloxane, aminopropyl-terminated polydimethylsiloxane and / or carboxyl-polydimethylsiloxane.

[0034] The hydrophobic coating can alternatively be based on or consist of fluorinated compounds, in particular fluorinated silanes or alkylsilanes. Preferred are: - Henicosyl-1,1,2,2-tetrahydrododecyldimethyltris(dimethylaminosilane), - Heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane (FDTS), - Nonafluoro-1,1,2,2-tetrahydrohexyltris(dimethylamino)silane, - 3,3,3,4,4,5,5,6,6-nonafluorohexyltrichlorosilane, - Tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS), - Bis(tridecafluoro-1,1,2,2-tetrahydrooctyl)dimethylsiloxymethylchlorosilane, - Dodecyltrichlorosilane (DDTS), - Dimethyldichlorosilane (DDMS), - 10-Undecenyltrichlorosilane (V11), - Pentafluorophenylpropyltrichlorosila.

[0035] The hydrophobic coating may be a hybrid coating containing organic and inorganic compounds, for example selected from those mentioned above.

[0036] The hydrophobic coating preferably has a layer thickness of 5 nm to 1 µm, particularly preferably 10 nm to 500 nm, and especially 20 nm to 150 nm. These coating thicknesses offer a good balance between stability and transparency. The layer thickness of the hydrophobic coating is preferably essentially constant, with a maximum local deviation of 5% from the selected layer thickness.

[0037] The thickness of layers and coatings can be determined using methods such as scanning electron microscopy, interference microscopy, atomic force microscopy, or light microscopy, depending on the thickness range. For layers in the nanometer range, X-ray reflectometry (XPR) or a scanning electron microscope (SEM) in combination with a focused ion beam (FIB) can also be used to measure the layer thickness. Measurement methods for determining layer thickness are familiar to those skilled in the art. Scanning electron microscopy is preferred.

[0038] The reflective layer covers the entire display area. It can optionally extend beyond the display area. In one embodiment, however, it is arranged exclusively in the masking area and does not extend into the see-through area. This is particularly the case if the reflective layer would excessively reduce the transparency of the see-through area due to an excessively high degree of reflection.

[0039] The reflective layer can be formed as a reflective coating on the outside surface of the outer pane, the inside surface of the outer pane, the outside surface of the inner pane or the inside surface of the inner pane.

[0040] Since the display area is located in the opaque masking area of ​​the windshield, the reflective coating does not need to be transparent. It can therefore be mirror-like with a reflectance of at least 90% against radiation in the visible spectral range (in particular against the radiation of the imaging unit, measured at an angle of 60° to the surface normal). This is advantageous for achieving an intensive display image with low imaging unit power.Such a mirror-like reflective coating can, for example, be formed from a single layer based on a metal of sufficient thickness or from an optically highly refractive dielectric layer of sufficient thickness (for example, based on titanium oxide, aluminum nitride, silicon nitride, zirconium nitride, silicon-zirconium mixed nitride, zirconium oxide, tin oxide, zinc oxide, tin-zinc mixed oxide, silicon oxide, titanium carbide, zirconium carbide, or silicon-zirconium-aluminum). Coatings with multiple individual layers can also be used, for example, with at least one metal-based layer and at least one dielectric layer, or with multiple individual dielectric layers with different refractive indices.

[0041] However, partially transparent reflective coatings can also be used, which reflect only a portion of the radiation from the imaging unit and transmit a significant portion. Such reflective layers can also extend into the view-through area, provided their light transmission is sufficiently high so that they do not critically reduce transparency. In particular, they can also essentially completely cover the view-through area and fulfill an additional function there. For example, IR-reflective coatings can be used, which are intended to prevent the penetration of IR components of solar radiation in the view-through area and act as a reflective layer in the display area. Partially reflective reflective layers are typically formed as thin-film coatings, i.e., as a stack of thin layers.Coatings are known that contain at least one thin layer based on a metal, in particular silver, in addition to dielectric thin layers, for example based on silicon nitride, silicon-metal mixed nitrides such as silicon zirconium nitride, titanium oxide, aluminum nitride, tin oxide, zinc oxide, or tin-zinc mixed oxide. Thin layers based on a metal preferably have layer thicknesses of less than 50 nm, in particular less than 20 nm, to ensure the semi-transparent properties of the coating. Alternatively, purely dielectric coatings are also known, which comprise exclusively dielectric thin layers.Layers with a higher refractive index (e.g. based on titanium oxide or silicon nitride) and layers with a lower refractive index (e.g. based on silicon oxide) are arranged alternately and the reflective effect is caused by interference effects and can be adjusted very precisely by choosing the layer thicknesses.

[0042] The reflective layer can also be designed as a reflective film. Such a reflective film can be integrated into the intermediate layer, in particular, by placing it between two thermoplastic layers of the intermediate layer (preferably each formed from a thermoplastic film).

[0043] A reflective film can, for example, comprise a carrier film to which a reflective coating of the type described above is applied. The carrier film is, for example, based on PET and has a thickness of 10 µm to 200 µm. Alternatively, reflective films are also known that are formed from alternating polymeric individual layers with different refractive indices. At least one of the two layer types is preferably based on PET, with optical interference effects being achieved by alternating layers with different refractive indices. A mirror-like reflective film can also be formed from a metal foil, for example.

[0044] The invention is not limited to a specific type of reflective layer, but can in principle be implemented with any known reflective layer.

[0045] The opaque element forming the masking region is preferably an opaque masking print, preferably on the interior surface of the outer pane, alternatively on the exterior surface of the outer pane or on the exterior surface or the interior surface of the inner pane. The masking print is formed in particular from an enamel containing glass frits and a pigment, is screen-printed, and then fired into the pane surface. The pigment is typically a black pigment, for example carbon black, aniline black, bone black, iron oxide black, spinel black, and / or graphite. The masking print preferably has a thickness of 5 µm to 50 µm, particularly preferably 8 µm to 25 µm.

[0046] Alternatively, the masking area can also be formed by an opaque film in the intermediate layer, for example an opaque connecting film which ensures the adhesive connection of the outer and inner panes, or a specially designed opaque masking film, for example based on PET, which is inserted between two connecting films.

[0047] It is also possible for the masking region in the display area to be formed at least partially by a functional element with electrically controllable properties. Such a functional element can be, for example, an electrochromic element, an SPD element (suspended particle device), or a functional element based on liquid crystals. Such functional elements can be switched from an opaque to a transparent state. For example, it is possible to expand a static basic masking region, which is formed, for example, by a masking print, as needed by switching the functional element to the opaque state in another area of ​​the windshield in order to realize an enlarged display area.Such a functional element can be applied directly to the interior surface of the outer pane or the exterior or interior surface of the inner pane or can be embedded in the intermediate layer as a functional film.

[0048] In a typical embodiment, the masking area surrounds the see-through area in a frame-like manner. The masking area is thus arranged circumferentially around the see-through area. Typically, the masking area forms the circumferential edge area of ​​the windshield and borders the circumferential side edge of the windshield. Therefore, in a preferred embodiment, the masking area is arranged in a circumferential edge area of ​​the windshield and surrounds the central see-through area.

[0049] The windshield has an upper edge and a lower edge as well as two side edges running in between. The upper edge refers to the edge which is intended to point upwards in the installed position. The lower edge refers to the edge which is intended to point downwards in the installed position. The upper edge is often also referred to as the roof edge and the lower edge as the engine edge. If the masking area is arranged in a circumferential edge region of the windshield, the upper edge, the lower edge and the two side edges are each assigned a section of the masking area which extends along the respective edge and preferably borders on it. The display area is preferably arranged in the section of the masking area which is assigned to the lower edge. In other words, the display area is preferably arranged between the see-through area and the lower edge.

[0050] The at least one ultrasonic transmitter is designed to vibrate at least a portion of the windshield area provided with the hydrophobic coating, as needed, to remove condensed moisture in this area, particularly by causing the water droplets on the hydrophobic coating to drip, slide, or roll off. Preferably, the entire area of ​​the windshield provided with the hydrophobic coating is vibrated. Particularly preferably, the hydrophobic coating is present on the entire display area, and the entire display area is vibrated.

[0051] The ultrasound transmitter can, for example, have a piezoelectric (or piezoceramic) or magnetostrictive transducer system to generate the ultrasound waves. The frequency of the ultrasound is preferably in the range of 20 kHz to 200 kHz.

[0052] The ultrasonic transmitter can be attached to the windshield. The ultrasonic transmitter can be attached directly to the windshield, for example, by gluing or clamping, or it can be housed in a housing that is attached to the windshield, for example, by gluing or clamping.

[0053] In a first preferred embodiment, at least one ultrasonic transmitter is attached to the lower edge of the windshield. A single ultrasonic transmitter can be used, mounted along the entire width of the display area at the lower edge. Alternatively, a plurality of directly adjacent ultrasonic transmitters can be used, with all of the ultrasonic transmitters being mounted along the entire width of the display area at the lower edge. The ultrasonic transmitter (or all of the ultrasonic transmitters) can be mounted along the entire length of the lower edge or at least along a large part of the lower edge (preferably at least 80% of the length of the lower edge, particularly preferably at least 90%).

[0054] However, it is also possible for one or more ultrasonic transmitters to be mounted only on a localized area of ​​the lower edge and only along a portion of the width of the display area. This can be particularly useful if only a portion of the display area is to be freed of condensed moisture. Projecting the area to be freed of moisture onto the lower edge creates a projection section of the lower edge, with the ultrasonic transmitter mounted on this projection section.

[0055] In a second preferred embodiment, at least one ultrasonic transmitter is attached to (at least) one side edge of the windshield. The ultrasonic transmitter can be attached to one side edge only, or ultrasonic sensors can be attached to both sides of the windshield. Projecting the display area onto the side edge creates a projection section of the side edge, with the ultrasonic transmitter preferably being attached to this projection section. Particularly preferably, the ultrasonic transmitter is attached to that area of ​​the side edge that belongs to the section of the masking area associated with the lower edge (if the display area is arranged in this section of the masking area).

[0056] In these embodiments, the ultrasonic transmitter is advantageously arranged close to the display area so that it can be set into vibration with a comparatively low power.

[0057] It is also possible that the ultrasonic transmitter is not attached to the windshield, but to the vehicle body, in such a way that it is in contact with the windshield when it is installed, in particular its lower edge or side edge, as described above.

[0058] However, the ultrasonic transmitter does not have to be in contact with the windshield or even attached to it. Alternatively, the ultrasonic transmitter can be positioned in front of the windshield so that it irradiates the interior surface of the inner pane. The ultrasonic transmitter can be positioned, in particular, near the vehicle's instrument panel. The ultrasonic waves are transmitted through the air and strike the interior surface of the inner pane, particularly the area of ​​the interior surface coated with the hydrophobic coating.

[0059] In the installed position, the windshield is preferably arranged at an angle (installation angle) to the vertical of 45° to 75° and is installed accordingly in the vehicle. The installation angle is particularly preferably from 50° to 70°, even more preferably from 55° to 65°, for example approximately 60°, as is usual in passenger cars. With such a large installation angle, the advantages of the invention become particularly apparent because the display area (between the viewing area and the lower edge of the windshield) is difficult for the user to reach and therefore cannot easily be manually cleaned of moisture. The installation angle refers to the angle that the windshield makes with the vertical. The windshield is typically curved, at least if the vehicle is a passenger car.In this case, the installation angle is determined at the geometric center of the windshield (which is typically located in the viewing area) and the tangential plane of the outside surface of the outer pane is used.

[0060] The outer pane and the inner pane are preferably made of glass, in particular soda-lime glass, which is common for window panes. However, the panes can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass) or transparent plastics (e.g., polymethyl methacrylate or polycarbonate). The thickness of the outer pane and the inner pane can vary widely. Preferably, panes with a thickness in the range of 0.8 mm to 5 mm, more preferably 1 mm to 3 mm, are used, for example, with the standard thicknesses of 1.6 mm or 2.1 mm.

[0061] The outer pane, the inner pane, and the thermoplastic interlayer can be clear and colorless, but also tinted or colored. The outer pane and the inner panes can independently be non-tempered, semi-tempered, or thermally or chemically toughened.

[0062] The windshield is preferably curved in one or more directions of space, as is common for motor vehicle windshields (particularly windshields of passenger cars), with typical radii of curvature ranging from approximately 10 cm to approximately 40 m. Typically, the outer surface of the outer pane has a convex curve, and the interior surface of the inner pane has a concave curve. However, the windshield can also be flat, for example, if it is intended as a windshield for buses, trains, or tractors.

[0063] The thermoplastic intermediate layer contains at least one thermoplastic polymer, preferably polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), or polyurethane (PU), or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The intermediate layer is typically formed from at least one thermoplastic film (connecting film), preferably based on one of the said polymers, in particular based on PVB. In the context of the invention, this means that the film predominantly contains the said material (a proportion of greater than 50% by weight) and can optionally contain further components, for example plasticizers, stabilizers, UV or IR absorbers. The thickness of the intermediate layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.5 mm to 1 mm.

[0064] In an advantageous development of the invention, the arrangement further comprises a humidity sensor, which is assigned to the windshield in such a way that it is suitable for detecting condensed moisture on the display area. The humidity sensor can be attached to the windshield or integrated into the windshield, for example as a capacitive or optical humidity sensor. A capacitive humidity sensor is typically integrated into the windshield and forms a type of capacitive button in the display area. If the capacitance of the interior surface changes due to the presence of moisture, this is detected by the sensor. An optical humidity sensor can, for example, be attached to the exterior surface of the outer pane or integrated into the intermediate layer.It typically includes a light source that illuminates the interior surface of the inner pane at an angle greater than the critical angle of total internal reflection. The presence of moisture inhibits total internal reflection, changing the signal from a light sensor that measures the reflected radiation.

[0065] The humidity sensor can also be positioned at a distance from the windshield and in front of the windshield (for example, near the vehicle's instrument panel). Such humidity sensors are typically also optical sensors that detect the presence of moisture, for example, via a change in reflection behavior.

[0066] In a particularly preferred embodiment, the arrangement further comprises a control unit connected to the ultrasonic transmitter and the humidity sensor. The control unit is suitable and designed to activate the ultrasonic transmitter when the humidity sensor detects condensed moisture on the display area. This allows the removal of the moisture to be initiated automatically, without requiring any user intervention.

[0067] The windshield can be manufactured using conventional processes. The outer and inner panes are laminated together via the interlayer, for example, using autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof. The bonding of the outer and inner panes is typically achieved using heat, vacuum, and / or pressure.

[0068] The hydrophobic coating and the reflective coating (if the reflective layer is designed as such) are preferably applied to the respective pane before lamination. Alternatively, the hydrophobic coating can also be applied after lamination, because the interior surface of the inner pane is still exposed. The same applies to the reflective coating if it is also applied to the interior surface of the inner pane.

[0069] The hydrophobic coating can be applied, for example, using the sol-gel process. Such coatings can be produced with particularly high optical quality and a particularly thin thickness. A further advantage of the sol-gel process is that, as a wet-chemical process, it offers high flexibility, allowing, for example, the coating to be applied to only parts of the pane surface, such as the display area according to the invention or part of it.The coating process can, for example, proceed as follows: The sol is applied to the interior surface of the inner pane, in particular by wet-chemical processes, for example by dip coating, spin coating, flow coating, application by roller or brush or by spray coating, or by printing processes, for example by pad printing or screen printing. The sol is then condensed. The condensation can comprise a temperature treatment, which can be carried out as a separate temperature treatment at, for example, up to 500°C or as part of a glass bending process, typically at temperatures of 600°C to 700°C. If the precursors have UV-crosslinkable functional groups (for example methacrylate, vinyl or acrylate groups), the condensation can comprise a UV treatment.Alternatively, the condensation can include an IR treatment for suitable precursors (e.g., silicates). Optionally, solvent can be evaporated, for example, at a temperature of up to 120 °C. The application of layers using the sol-gel process is known to those skilled in the art, and further information can be found, for example, in WO2021209201A1.

[0070] Alternatively, the hydrophobic coating can also be applied using chemical vapor deposition (CVD). The hydrophobic coating is preferably applied using plasma-enhanced chemical vapor deposition (PECVD), especially under atmospheric pressure (APCVD). The advantage of plasma-enhanced chemical vapor deposition is the speed of application combined with the high level of homogeneity of the layers compared to many other processes. Silicon oxide-containing compounds, in particular, can be applied homogeneously and efficiently to a substrate using this method.

[0071] Alternatively, the hydrophobic coating can be applied by physical vapor deposition (PVD), particularly preferably by cathode sputtering, and even more preferably by magnetic field-assisted cathode sputtering. Alternatively, the hydrophobic coating can also be applied to the wafer by atomic layer deposition (ALD). In this process, ultra-thin layers are created through the cyclic chemical reaction of precursor molecules. A major advantage of the ALD method is the precise control over the layer thickness and composition, which results in a particularly homogeneous and uniform coating.

[0072] The reflective layer can be provided as a reflective foil and inserted into the intermediate layer or deposited as a reflective coating on one of the panes. The reflective coating is preferably deposited by PVD, particularly preferably by sputtering, and most preferably by magnetron sputtering. In principle, however, the coating can also be applied using CVD, for example, PECVD, vapor deposition, or ALD.

[0073] If the windshield is to be curved, the outer and inner panes are subjected to a bending process, preferably before lamination and preferably after coating. The outer and inner panes are preferably bent congruently together (i.e., lying one on top of the other, simultaneously, and using the same tool), as this ensures the shape of the panes is optimally matched for subsequent lamination. Typical temperatures for glass bending processes are, for example, 500°C to 700°C. All standard bending methods can be used, such as gravity bending, press bending, and / or suction bending.

[0074] The invention also encompasses a display system for a vehicle. The display system comprises an arrangement according to the invention for removing condensed moisture and at least one imaging unit directed toward and irradiating the display area of ​​the windshield.

[0075] At least one imaging unit is directed at one display area of ​​the windshield. It is arranged on the interior side of the windshield and illuminates the windshield via the interior surface of the inner pane. When the display system is in operation, the radiation emitted by the imaging unit illuminates the display area to generate the projection or display image. The radiation from the imaging unit is (at least partially) reflected by the reflective layer toward the viewer, creating a virtual image that the viewer perceives slightly behind the reflective plane (reflective coating).

[0076] The radiation from the imaging unit lies in the visible spectral range of the electromagnetic spectrum, specifically in the spectral range from 450 nm to 650 nm - typical imaging units work with RGB colors (red, green, blue), for example with a wavelength of 450 to 475 nm (blue), a wavelength of 520 nm to 550 nm (green) and a wavelength of 620 to 650 nm (red).

[0077] The imaging unit is preferably a projector or a screen ("display", electronic display). A screen is particularly preferred. In principle, any type of screen can be used for the display system according to the invention, for example a field emission display (FED), a liquid crystal display (LCD), a thin-film transistor display (TFT-LCD), a cathode ray tube display (CRT), a plasma display, an organic light-emitting diode (OLED), a (true) LED display, or a surface-conduction electron emitter display (SED). OLED and LCD screens are particularly common.

[0078] In projectors, the beam direction can typically be varied using mirrors, particularly vertically, to adapt the projection to the viewer's height. Screens can be rotatably mounted, which means the beam direction (particularly vertically) can be varied to adapt the projection to the viewer's height. The area in which the viewer's eyes must be located for a given setting of the beam direction is called the eyebox window. This eyebox window can be moved vertically by adjusting the mirrors of a projector or by adjusting the orientation of the screen (if the screen is rotatably mounted). The entire accessible area (i.e. the superposition of all possible eyebox windows) is called the eyebox. A viewer located inside the eyebox can perceive the virtual image.This, of course, means that the viewer's eyes must be within the eyebox, not the entire body. The technical terms used here from the field of HUDs are generally familiar to those skilled in the art. For a detailed description, please refer to the dissertation "Simulation-based Measurement Technology for Testing Head-Up Displays" by Alexander Neumann at the Institute of Computer Science at the Technical University of Munich (Munich: University Library of the Technical University of Munich, 2012), particularly Chapter 2, "The Head-Up Display."

[0079] It is possible to use multiple imaging units, with each imaging unit irradiating only a portion of the display area. This can be particularly useful for very large display areas, for example, if the display area is to extend along the entire lower edge of the windshield. In this case, multiple imaging units (e.g., screens) located next to one another can be used, with the entire display area being irradiated by the entire imaging units. The display area can then be conceptually divided into several sub-display areas, with each sub-display area being assigned to and irradiated by exactly one imaging unit.

[0080] In an advantageous embodiment, the display system is operated with p-polarized radiation. The imaging unit irradiates the display area with p-polarized radiation. This means that the radiation from the at least one imaging unit has a p-polarized radiation component, preferably is predominantly p-polarized, i.e. has a p-polarized radiation component of more than 50%, particularly preferably at least 80%, and most particularly preferably at least 95%. In particular, the radiation is essentially purely p-polarized - the p-polarized radiation component is therefore 100% or deviates only insignificantly therefrom. The specification of the polarization direction refers to the plane of incidence of the radiation on the windshield. P-polarized radiation refers to radiation whose electric field oscillates in the plane of incidence.S-polarized radiation refers to radiation whose electric field oscillates perpendicular to the plane of incidence. The plane of incidence is spanned by the incidence vector and the surface normal of the windshield at a point within the display area, preferably in the geometric center of the display area. If multiple imaging units are used, with each imaging unit irradiating a partial area of ​​the display area (partial display area), this refers for each imaging unit to the partial display area irradiated by it, regardless of the other imaging units. Due to the windshield curvature common in vehicles, which affects the plane of incidence and thus the definition of polarization, the polarization components (in particular the ratio of p-polarized radiation to s-polarized radiation or vice versa) may differ from this reference point at other locations.To generate the desired polarized radiation, a polarization filter or a polarizing beam splitter can be arranged between the imaging unit and the windshield in the beam path, for example, if the imaging unit itself does not already provide radiation of the desired polarization direction.

[0081] The advantage of p-polarized radiation is, on the one hand, that the displayed image is visible to wearers of polarization-selective sunglasses, which typically only allow p-polarized radiation to pass through and block s-polarized radiation. On the other hand, p-polarized radiation opens up the possibility of arranging the reflective layer anywhere on the windshield without creating an undesirable ghost image due to reflection from the interior surface of the inner pane. Since the angle of incidence typically does not deviate significantly from the Brewster angle, p-polarized radiation is generally not reflected, or only reflected to a small extent, from the interior surface of the inner pane. The reflection of the radiation from the imaging unit is due almost exclusively to the reflective layer.

[0082] Alternatively, the imaging unit can also be operated with s-polarized radiation, especially if the reflective layer is arranged on the interior surface of the inner pane. In this case, there is only one reflection plane for the radiation, and ghost images are eliminated.

[0083] The angle of incidence of the radiation onto the windshield is preferably between 45° and 70°, particularly preferably between 60° and 70°, for example approximately 65°. This is particularly advantageous when the imaging unit is operated with p-polarized radiation. These angles of incidence deviate only slightly from the Brewster angle. The Brewster angle for an air-glass transition in the case of soda-lime glass, which is generally used for window panes, is 57.2° (with a refractive index of soda-lime glass of 1.55 at a wavelength of 550 nm). The angle of incidence can also be referred to as the angle of incidence. It is the angle between the incidence vector of the radiation and the interior-side surface normal (i.e., the surface normal to the interior-side surface of the inner pane), determined at a point in the display area, preferably in the geometric center of the display area.If multiple imaging units are used, with each imaging unit irradiating a sub-area of ​​the display area (partial display area), this refers to the partial display area irradiated by each imaging unit, independently of the other imaging units. If the angle of incidence corresponds exactly to the Brewster angle, only s-polarized radiation is reflected, not p-polarized radiation. In an advantageous embodiment, the angle of incidence deviates from the Brewster angle by a maximum of 10°.

[0084] The invention further encompasses a vehicle equipped with the arrangement according to the invention or the display system according to the invention. The vehicle can, in principle, be any land, air, or water vehicle. The vehicle is preferably a motor vehicle or rail vehicle, particularly preferably a passenger car or truck. The above statements regarding the arrangement and the display system apply accordingly to the vehicle.

[0085] The arrangement according to the invention can be used to perform a method for removing condensed moisture from a windshield display area, wherein the ultrasonic transmitter causes the windshield display area to vibrate (more precisely: at least the part of the display area provided with the hydrophobic coating), so that condensed moisture is removed from the hydrophobic coating, in particular by dripping, sliding, or rolling off. The above statements regarding the arrangement apply accordingly to the method.

[0086] In an advantageous development of the method, the arrangement further comprises a humidity sensor and a control unit connected to the ultrasonic transmitter and the humidity sensor. The control unit activates the ultrasonic transmitter when the humidity sensor detects condensed moisture on the display area.

[0087] In addition to removing condensed moisture, ultrasound can also be used to clean the display area. The cleaning effect is primarily achieved through cavitation. The ultrasound causes bubbles to form in the liquid, which collapse, releasing energy that removes contaminants such as dirt or fingerprints from the screen surface. It may sometimes be necessary to operate the ultrasonic transmitter at a higher power than is required for purely moisture removal.

[0088] The invention is explained in more detail below with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way.

[0089] They show: Fig. 1 a plan view of a generic windshield, Fig. 2 a cross-section through the windscreen Fig. 1 in a generic display system, Fig. 3 cross sections through a region of the windshield of two embodiments of the arrangement according to the invention, Fig. 4 Top views of the windshield in three embodiments of the arrangement according to the invention, Fig. 5 a cross section through a further embodiment of the arrangement according to the invention, Fig. 6 a cross section through a further embodiment of the arrangement according to the invention.

[0090] Fig. 1 shows a plan view of a generic windshield 10. It is the windshield of a passenger car. Fig. 2 shows a cross section through the windshield 10 from Fig. 1, which functions as a projection surface in a generic display system.

[0091] The display system comprises the windshield 10 and an imaging unit 4, which is directed toward a display area A of the windshield 10. In the display area A, the imaging unit 4 can generate images that are perceived by an observer 5 (vehicle driver) as virtual images on the side of the windshield 10 facing away from him when his eyes are located within the so-called eyebox E.

[0092] The windshield 10 is constructed from an outer pane 1 and an inner pane 2, which are connected to one another via a thermoplastic intermediate layer 3. Its lower edge U is arranged downwards towards the engine of the passenger car, its upper edge O upwards towards the roof. Two side edges S run between the lower edge U and the upper edge O. In the installed position, the outer pane 1 faces the outside environment, while the inner pane 2 faces the vehicle interior. The outer pane 1 and the inner pane 2 are made of soda-lime glass with a thickness of 2.1 mm for the outer pane 1 and 1.6 mm for the inner pane 2. The intermediate layer 3 is made of a 0.76 mm thick PVB film. The windshield 10 is shown flat for the sake of simplicity, although real windshields typically have a spherical curvature.

[0093] The outer pane 1 has an outer surface I facing the outside environment and an interior surface II facing the vehicle interior. Likewise, the inner pane 2 has an outer surface III facing the outside environment and an interior surface IV facing the vehicle interior.

[0094] The windshield 10 has an opaque masking area M arranged in a peripheral edge region and surrounding a transparent see-through area D in a frame-like manner. Such masking areas M are common in vehicle windshields – they primarily serve to protect the adhesive used to bond the windshield 10 to the vehicle body from UV radiation.

[0095] The display area A is located in the masking area M between the view-through area D and the lower edge U. Such a display system can also be referred to as a "black-print display." This display area A is used to display information for the vehicle occupants. This can include, in particular, vehicle status information (e.g., driving speed or a fuel gauge), navigation instructions (e.g., speed limits or directions), or the image from a rear-facing camera. Entertainment content (e.g., films, internet data, or computer games) can also be displayed, particularly on the passenger side.

[0096] The imaging unit 4 is, for example, an LCD screen. Since the display area A is comparatively large and extends along a large part of the lower edge U, a plurality of such imaging units 4 are typically used, with each imaging unit 4 irradiating a portion of the display area A. The imaging unit 4 irradiates the display area A with an angle of incidence α, which is measured to the interior-side surface normal of the inner pane. The angle of incidence α is, for example, 65°, which is comparatively close to the Brewster angle (approximately 57° for an air-soda-lime-glass transition). The radiation from the imaging unit 4 is p-polarized – it is therefore hardly reflected by the glass surfaces.

[0097] To generate the display image, the windshield 10 is equipped with a reflective coating in the display area A, which is not shown in the figure for simplicity. The reflective coating reflects the p-polarized radiation from the imaging unit 4 to generate the display image. Since it represents the only significant reflective interface, a clear display image is generated with no (or only very low-intensity) ghost images.

[0098] Fig. 3(a) shows a cross-section through a region adjacent to the lower edge U of an embodiment of the windshield 10 of an arrangement according to the invention. The masking region M is formed by an opaque cover print 6, which is arranged on the interior-side surface II of the outer pane 1. The windshield 10 is equipped in the display region A with a reflective layer 7, which is implemented as a coating on the interior-side surface IV of the inner pane 2. The reflective layer 7 serves to reflect the radiation of the imaging unit 4. A hydrophobic coating 8 is also arranged on the interior-side surface IV of the inner pane 2, on the reflective layer 7. The hydrophobic coating 8 represents the uppermost layer on the interior-side surface IV of the inner pane 2 and is accordingly exposed.

[0099] Fig. Figure 3(b) shows a cross-section through a region adjacent to the lower edge U of a further embodiment of the windshield 10 of an arrangement according to the invention. Here, the reflective layer 7 is applied to the outer surface III of the inner pane 2 instead of to the interior surface IV. The opaque cover print 6 is also arranged here on the interior surface II of the outer pane 1. The hydrophobic coating 8 is again arranged on the interior surface IV of the inner pane 2, in this case directly on said surface.

[0100] The illustrated embodiments represent preferred combinations of masking print 6, reflective layer 7, and hydrophobic coating 8, but do not limit the invention. Masking print 6 and reflective layer 7 can also be arranged on other surfaces. Reflective layer 7 can also be embedded in intermediate layer 3. The only important thing is the following order of the coatings, based on a viewing direction through windshield 10, starting from the vehicle interior to the external environment: hydrophobic coating 8 - reflective layer 7 - masking print 6 (or another opaque element forming masking region M). Only hydrophobic coating 8 must be arranged on the interior-side surface IV of inner pane 2, specifically as the uppermost and exposed layer.

[0101] Fig. Figure 4(a) shows a plan view of an embodiment of the windshield 10 of an arrangement according to the invention. The windshield 10 is equipped with an ultrasonic transmitter 20. The ultrasonic transmitter 20 is mounted on the lower edge U of the windshield 10, along the entire width of the display area A.

[0102] The hydrophobic coating 8 increases the contact angle for water, so that condensed moisture wets the surface less. The moisture is present primarily in the form of separate water droplets with a comparatively small contact area with the surface. The ultrasonic transmitter 20 causes the display area A to vibrate, causing the water droplets to drip, slide, or roll off the surface. This advantageously removes the condensed moisture quickly from the display area A, so that the projection in the display area A is clearly visible to the user.

[0103] Fig. 4(b) shows a plan view of a further embodiment of the windshield 10 of an arrangement according to the invention. In this case, the ultrasonic transmitter 20 is also attached to the lower edge U, but not along the entire width of the display area A, but only along a portion of the total extent of the display area A. This can be advantageous if only a portion of the display area A is to be freed of condensed moisture, for example, a portion in which particularly important information for the driver is displayed. In this case, it may also be desirable for the hydrophobic coating 8 not to be present on the entire display area A, but only on the portion of the display area directly above the ultrasonic transmitter 20.

[0104] Fig. Figure 4(c) shows a plan view of another embodiment of the windshield 10 of an arrangement according to the invention. In this case, ultrasonic transmitters 20 are mounted on both sides of the side edges S of the windshield 10, and are located in the lower region of the windshield 10, where the display area A is also located.

[0105] Fig. Figure 5 shows a cross-section through a further embodiment of the windshield 10 of an arrangement according to the invention. The ultrasonic transmitter 20 is not attached to the windshield 10, but rather is arranged at a certain distance in front of it. The ultrasonic transmitter 20 can, for example, be integrated in the area of ​​the vehicle's instrument panel. It irradiates the interior surface IV in the display area A with ultrasonic waves to cause the display area A to vibrate.

[0106] Fig. 6 shows a cross section through a further development of the arrangement according to the invention according to Fig.5. The arrangement includes a humidity sensor 30, which is also arranged in the area of ​​the vehicle's instrument panel in front of the windshield 10. The humidity sensor 30 detects (for example, optically) the presence of moisture on the display area A. The humidity sensor 30 and the ultrasonic transmitter 20 are connected to a control unit 40. If condensed moisture on the display area A is detected by the humidity sensor 30, the control unit 40 activates the ultrasonic transmitter 20. The ultrasonic transmitter 20 is thus automatically activated, and the moisture is removed without the user having to take any action, for example, by manually activating the ultrasonic transmitter 20 using a control button or a switch.

[0107] The arrangement shown is merely an example. Humidity sensors 30 and control units 40 can also be combined with such ultrasonic transmitters 20 that are mounted on the windshield 10. The humidity sensor 30 can also be integrated directly into the windshield or mounted on the windshield, for example, as a capacitive or optical humidity sensor. List of reference symbols: 10 Windshield 1 outer pane 2 inner pane 3 thermoplastic intermediate layer 4 imaging unit 5 viewers / vehicle drivers 6 Cover print 7 Reflective layer 8 hydrophobic coating 20 ultrasonic transmitters 30 Humidity sensor 40 Control unit O Top edge of the windshield 10 U Lower edge of the windshield 10 S Side edge of the windshield 10 D See-through area M Masking area A Windshield display area 10 E Eyebox α angle of incidence I outside surface of the outer pane 1 II Interior surface of the outer pane 1 III outer surface of the inner pane 2 IV Interior surface of the inner pane 2 X - X' intersection line QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2009071135A1

[0004] EP 1800855B1

[0004] EP 1880243A2

[0004] DE 102014220189A1

[0004] EP 3187917B1

[0004] WO 2021104800A1

[0004] DE 102009020824A1

[0005] WO 2022073894A1

[0005] WO 2022073860A1

[0005] WO 2022238101A1

[0008] CN 206704151U

[0009] CN 117896597A

[0009] WO 2021209201A1

[0069] Cited non-patent literature

[0000] Simulation-based measurement technology for testing head-up displays” by Alexander Neumann at the Institute of Computer Science at the Technical University of Munich (Munich: University Library of the TU Munich, 2012

[0078]

Claims

[1] An arrangement for removing condensed moisture from a display area of ​​a windshield, comprising: - a windshield (10) comprising an outer pane (1) with an outer surface (I) and an interior surface (II) and an inner pane (2) with an outer surface (III) and an interior surface (IV), wherein the interior surface (II) of the outer pane (1) and the outer surface (III) of the inner pane (2) are connected to one another via a thermoplastic intermediate layer (3), which has a transparent see-through area (D) and an opaque masking area (M) and which has a display area (A) arranged in the masking area (M), and which is provided at least in the display area (A) with a reflection layer (7) which is suitable for reflecting radiation in the visible spectral range, wherein at least in a part of the display area (A) on the interior-side surface (IV) of the inner pane (2), a hydrophobic coating (8) is arranged as the uppermost exposed layer, - an ultrasonic transmitter (20) which is associated with the windscreen (10) in such a way that it is suitable for causing at least said part of the display area (A) to vibrate. [2] Arrangement according to claim 1, wherein the ultrasonic transmitter (20) is mounted on a lower edge (U) or on a side edge (S) of the windshield (10). [3] Arrangement according to claim 1, wherein the ultrasonic transmitter (20) is arranged in front of the windshield (10) in such a way that it irradiates the interior-side surface (IV) of the inner pane (2). [4] Arrangement according to one of claims 1 to 3, wherein the contact angle of water to the hydrophobic coating (8) is more than 80°, preferably more than 90°. [5] Arrangement according to one of claims 1 to 4, wherein the windshield (10) is arranged with an installation angle to the vertical of 45° to 75° and wherein the display area (A) is arranged between the viewing area (D) and a lower edge (U) of the windshield (10). [6] Arrangement according to one of claims 1 to 5, which comprises a humidity sensor (30) which is associated with the windshield (10) in such a way that it is suitable for detecting condensed moisture on the display area (A). [7] Arrangement according to claim 6, which comprises a control unit (40) which is connected to the ultrasonic transmitter (20) and the humidity sensor (30), wherein the control unit (40) is suitable for activating the ultrasonic transmitter (20) when the humidity sensor (30) detects condensed moisture on the display area (A). [8] Display system for a vehicle, comprising - an arrangement according to one of claims 1 to 7 and - at least one imaging unit (4) which is directed towards and irradiates the display area (A) of the windscreen (10). [9] Display system according to claim 8, wherein the imaging unit (4) irradiates the display area (A) with p-polarized radiation and with an angle of incidence (α) of 60° to 70°. [10] A vehicle equipped with an arrangement according to any one of claims 1 to 7 or a display system according to claim 8 or 9.

Images